If you watch tonight's episode of "The Vampire Diaries" and think, "Man, this feels like a completely different show!" don't be alarmed. It is, for all intents and purposes, a completely different show. For those who don't religiously follow TV news, the episode may seem to come out of the blue. Titled "The Originals," features Klaus as the lead character, instead of a secondary player. It leaves behind Mystic Falls and the Salvatore brothers to introduce several new characters in the decadent setting of New Orleans' French Quarter, and strikes a much more adult, dark, complicated tone than we've seen so far on "The Vampire Diaries."We've been seeing a lot of confusion around Twitter, so we thought we'd answer some of your questions about the backdoor pilot to help ease the transition to "The Originals."Q: What is a backdoor pilot/planted spinoff, anyway?A: A planted spinoff (also known as a backdoor pilot) is an episode of...